PROCESS FOR IMPROVING BASE OIL YIELDS

An improved process for making a base oil and for improving base oil yields by combining an atmospheric resid feedstock with a base oil feedstock and forming a base oil product via hydroprocessing. The process generally involves subjecting a base oil feedstream comprising the atmospheric resid to hydrocracking and dewaxing steps, and optionally to hydrofinishing, to produce a light and heavy grade base oil product. A process is also disclosed for making a base oil having a viscosity index of 120 or greater from a base oil feedstock having a viscosity index of about 100 or greater that includes a narrow cut-point range vacuum gas oil. The invention is useful to make Group II and/or Group III/III+ base oils, and, in particular, to increase the yield of a heavy base oil product relative to a light base oil product produced in the process.